Anki
Anki is a free, open-source flashcard app built on spaced repetition, with versions for Windows, macOS, Linux, Android and the web; the iOS app is paid. It gives deep control over cards and scheduling, but takes time to learn.
Is Anki free?
Yes. Anki is free on Windows, Mac, Linux, Android and the web, including sync between devices. The only paid version is AnkiMobile, the iPhone and iPad app, which costs US$24.99 once. There is no subscription.
Which platforms does Anki run on?
Anki runs on Windows, Mac, Linux, the web, Android, and iPhone and iPad. The Android app, AnkiDroid, is made by a separate team of volunteers. Your cards are stored on each device, so you can review offline, and they sync through AnkiWeb.
| Platform | App | Price | Notes |
|---|---|---|---|
| Web | AnkiWeb (official) | Free | Review cards and create basic text-only cards. Shared deck downloads and media need the desktop app. |
| iPhone and iPad | AnkiMobile (official) | US$24.99 one-time | Requires iOS 15.2 or later. |
| Android | AnkiDroid (third-party) | Free | Built by a separate group of volunteer contributors, with its own support site. Linked from Anki’s website, and it syncs through AnkiWeb. |
| Mac | Anki (official) | Free | Requires macOS 13 or later (Apple silicon or Intel). |
| Windows | Anki (official) | Free | Requires Windows 10 or later (x64), or Windows 11 on ARM. |
| Linux | Anki (official) | Free | Supports Linux distributions from 2022 on x64, and from 2024 on ARM. |
How does Anki schedule reviews?
By default, Anki uses an algorithm based on SM-2: each time you remember a card, its next interval is multiplied by an ease factor. You can switch to FSRS in the deck options. FSRS estimates how likely you are to remember each card and schedules the review when that probability falls to a target you set, 90% by default.
- Grading
- Four buttons: Again, Hard, Good, Easy.
- Settings
- Presets of deck options: daily limits, learning and relearning steps (1m 10m by default), leech threshold (8 lapses), display order, easy days and, with FSRS, desired retention (90% by default) and optimisable parameters.
- Statistics
- Today’s totals and graphs of future due cards, review history, a calendar, intervals, ease or FSRS stability, difficulty and retrievability, hourly breakdown, answer buttons and true retention; plus per-card info.
What cards can you make in Anki?
Anki covers the common card types: question and answer (one way or both ways), type in the answer, cloze deletion (fill in the blank) and image occlusion (hide parts of an image). You can also design your own templates. Cards can include images, audio, video and maths, but there is no built-in AI to write them for you.
- Shared decks
- A public library of shared decks on AnkiWeb, downloaded through the desktop app.
- Import
- Anki packages (.apkg, .colpkg), text and CSV files, and Mnemosyne 2.0 databases.
- Export
- Deck packages (.apkg), collection packages (.colpkg) and notes as tab-separated plain text.
- Add-ons and integrations
- Add-ons for the desktop app, browsable in Anki or on AnkiWeb; updates to Anki can break them.
What are Anki's strengths and limits?
Strengths
- Free on desktop, Android and the web, including sync
- Open source, with a self-hostable sync server
- FSRS scheduler with an adjustable desired retention
- Large libraries of shared decks and add-ons
- Detailed statistics and fine-grained deck options
Limits
- Clunky interface
- Many settings, which take time to learn
- The iOS app costs US$24.99
- The web version can only create basic text-only cards
- Add-ons can stop working after an update
Our review
Anki is the best-known spaced repetition app. It is free almost everywhere, it can use FSRS, and its templates and add-ons let you build almost any kind of card. Its lead also owes a lot to a network effect: twenty years of shared decks, add-ons and tutorials have made it the default choice, which has long kept competitors at bay, whatever their merits.
The price of that power is a steep learning curve. Much of a product’s design work is deciding for its users: choosing what its makers believe is the best option and leaving the rest out. Anki rarely makes that call. Card templates, learning steps, daily limits and the scheduler itself are all left to you, across dozens of settings with little guidance on which ones matter. The result can feel clunky, and updates sometimes break the add-ons you rely on.
Anki suits learners who study a lot over months or years and are willing to put real time into learning the tool. If you want an app that works well out of the box, or a free app on iPhone, a simpler app will serve you better.